JLocke17 on "Malicious META refresh code."

Hello,

When I'm logged in I'm seeing this malicious META refresh code. I've not added. I believe my site was hacked recently.

However, when I'm not logged in, there is no such code. How do I find and fix it?

<META http-equiv="refresh" content="3;URL=http://adf.ly/xxxx/">

I'm thinking someone is making money out of my site by adding the code. It's not visible for public for some reasons. It just appears when I'm logged in.

Please help.

Thanks